Dr. Mary Claire Haver

We think about the pituitary.

But in the ovaries, we make estrogen, progesterone, and testosterone.

Estrogen is the hormone that will basically grow the lining of the uterus, get it ready for pregnancy.

You talk about estrogen all the time.

I'm not going to jump too far into it.

But when we talk about estrogen in the context of contraceptives, we're talking about ethanol estradiol.

And the thing to understand about estrogen is it is a class of molecules.

And so those are just compounds that in the body target a receptor.

And so I think about it as a lock and a key, right?

The key is the hormone.

The receptor is the lock.

And there's going to be different keys that fit into it differently.

So in the body, there are three natural progesterones made by girls to adults.

And in terms of the estrogens, those are estradiol, estrone, and estriol.

I know you know this.

You talk about it.

Well, birth control doesn't have any of those three.

And that's where the confusion starts.

So what does it typically have?

It has ethanol estradiol.